The Use of Simultaneously Administered ⁴⁷Ca and ⁴⁵Ca in the Study of Calcium Kinetics in the Rat

Abstract

A technique for measuring calcium kinetics in young rats is described, based on the two compartmental kinetic model of Heaney et al. It involves the simultaneous injection of ⁴⁷Ca and ⁴⁵Ca and the serial measurement of whole body retention and serum specific activity of the 2 isotopes respectively over 36 hours. The results in 2 groups of normal rats weighing 80 and 150 gm appear to validate the method as the values obtained for pool size and accretion rate in the 2 groups studied and the reduction of these parameters in the larger rats correspond closely to those shown by other workers using more conventional techniques.

This method is designed to overcome some of the practical problems of estimating calcium kinetics in the growing rat by avoiding the need for excreta collection and sacrifice of the animal by using ⁴⁷Ca retention, and by enhancing the counting efficiency for measuring serum specific activity by the simultaneous use of ⁴⁵Ca.

Key words

Calcium Kinetics - ⁴⁷Ca - ⁴⁵Ca